1 #ifndef _ASM_X86_PERCPU_H 2 #define _ASM_X86_PERCPU_H 3 4 #ifdef CONFIG_X86_64 5 #define __percpu_seg gs 6 #define __percpu_mov_op movq 7 #else 8 #define __percpu_seg fs 9 #define __percpu_mov_op movl 10 #endif 11 12 #ifdef __ASSEMBLY__ 13 14 /* 15 * PER_CPU finds an address of a per-cpu variable. 16 * 17 * Args: 18 * var - variable name 19 * reg - 32bit register 20 * 21 * The resulting address is stored in the "reg" argument. 22 * 23 * Example: 24 * PER_CPU(cpu_gdt_descr, %ebx) 25 */ 26 #ifdef CONFIG_SMP 27 #define PER_CPU(var, reg) \ 28 __percpu_mov_op %__percpu_seg:per_cpu__this_cpu_off, reg; \ 29 lea per_cpu__##var(reg), reg 30 #define PER_CPU_VAR(var) %__percpu_seg:per_cpu__##var 31 #else /* ! SMP */ 32 #define PER_CPU(var, reg) \ 33 __percpu_mov_op $per_cpu__##var, reg 34 #define PER_CPU_VAR(var) per_cpu__##var 35 #endif /* SMP */ 36 37 #ifdef CONFIG_X86_64_SMP 38 #define INIT_PER_CPU_VAR(var) init_per_cpu__##var 39 #else 40 #define INIT_PER_CPU_VAR(var) per_cpu__##var 41 #endif 42 43 #else /* ...!ASSEMBLY */ 44 45 #include <linux/kernel.h> 46 #include <linux/stringify.h> 47 48 #ifdef CONFIG_SMP 49 #define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x 50 #define __my_cpu_offset percpu_read(this_cpu_off) 51 #else 52 #define __percpu_arg(x) "%P" #x 53 #endif 54 55 /* 56 * Initialized pointers to per-cpu variables needed for the boot 57 * processor need to use these macros to get the proper address 58 * offset from __per_cpu_load on SMP. 59 * 60 * There also must be an entry in vmlinux_64.lds.S 61 */ 62 #define DECLARE_INIT_PER_CPU(var) \ 63 extern typeof(per_cpu_var(var)) init_per_cpu_var(var) 64 65 #ifdef CONFIG_X86_64_SMP 66 #define init_per_cpu_var(var) init_per_cpu__##var 67 #else 68 #define init_per_cpu_var(var) per_cpu_var(var) 69 #endif 70 71 /* For arch-specific code, we can use direct single-insn ops (they 72 * don't give an lvalue though). */ 73 extern void __bad_percpu_size(void); 74 75 #define percpu_to_op(op, var, val) \ 76 do { \ 77 typedef typeof(var) T__; \ 78 if (0) { \ 79 T__ tmp__; \ 80 tmp__ = (val); \ 81 } \ 82 switch (sizeof(var)) { \ 83 case 1: \ 84 asm(op "b %1,"__percpu_arg(0) \ 85 : "+m" (var) \ 86 : "qi" ((T__)(val))); \ 87 break; \ 88 case 2: \ 89 asm(op "w %1,"__percpu_arg(0) \ 90 : "+m" (var) \ 91 : "ri" ((T__)(val))); \ 92 break; \ 93 case 4: \ 94 asm(op "l %1,"__percpu_arg(0) \ 95 : "+m" (var) \ 96 : "ri" ((T__)(val))); \ 97 break; \ 98 case 8: \ 99 asm(op "q %1,"__percpu_arg(0) \ 100 : "+m" (var) \ 101 : "re" ((T__)(val))); \ 102 break; \ 103 default: __bad_percpu_size(); \ 104 } \ 105 } while (0) 106 107 #define percpu_from_op(op, var, constraint) \ 108 ({ \ 109 typeof(var) ret__; \ 110 switch (sizeof(var)) { \ 111 case 1: \ 112 asm(op "b "__percpu_arg(1)",%0" \ 113 : "=q" (ret__) \ 114 : constraint); \ 115 break; \ 116 case 2: \ 117 asm(op "w "__percpu_arg(1)",%0" \ 118 : "=r" (ret__) \ 119 : constraint); \ 120 break; \ 121 case 4: \ 122 asm(op "l "__percpu_arg(1)",%0" \ 123 : "=r" (ret__) \ 124 : constraint); \ 125 break; \ 126 case 8: \ 127 asm(op "q "__percpu_arg(1)",%0" \ 128 : "=r" (ret__) \ 129 : constraint); \ 130 break; \ 131 default: __bad_percpu_size(); \ 132 } \ 133 ret__; \ 134 }) 135 136 /* 137 * percpu_read() makes gcc load the percpu variable every time it is 138 * accessed while percpu_read_stable() allows the value to be cached. 139 * percpu_read_stable() is more efficient and can be used if its value 140 * is guaranteed to be valid across cpus. The current users include 141 * get_current() and get_thread_info() both of which are actually 142 * per-thread variables implemented as per-cpu variables and thus 143 * stable for the duration of the respective task. 144 */ 145 #define percpu_read(var) percpu_from_op("mov", per_cpu__##var, \ 146 "m" (per_cpu__##var)) 147 #define percpu_read_stable(var) percpu_from_op("mov", per_cpu__##var, \ 148 "p" (&per_cpu__##var)) 149 #define percpu_write(var, val) percpu_to_op("mov", per_cpu__##var, val) 150 #define percpu_add(var, val) percpu_to_op("add", per_cpu__##var, val) 151 #define percpu_sub(var, val) percpu_to_op("sub", per_cpu__##var, val) 152 #define percpu_and(var, val) percpu_to_op("and", per_cpu__##var, val) 153 #define percpu_or(var, val) percpu_to_op("or", per_cpu__##var, val) 154 #define percpu_xor(var, val) percpu_to_op("xor", per_cpu__##var, val) 155 156 /* This is not atomic against other CPUs -- CPU preemption needs to be off */ 157 #define x86_test_and_clear_bit_percpu(bit, var) \ 158 ({ \ 159 int old__; \ 160 asm volatile("btr %2,"__percpu_arg(1)"\n\tsbbl %0,%0" \ 161 : "=r" (old__), "+m" (per_cpu__##var) \ 162 : "dIr" (bit)); \ 163 old__; \ 164 }) 165 166 #include <asm-generic/percpu.h> 167 168 /* We can use this directly for local CPU (faster). */ 169 DECLARE_PER_CPU(unsigned long, this_cpu_off); 170 171 #endif /* !__ASSEMBLY__ */ 172 173 #ifdef CONFIG_SMP 174 175 /* 176 * Define the "EARLY_PER_CPU" macros. These are used for some per_cpu 177 * variables that are initialized and accessed before there are per_cpu 178 * areas allocated. 179 */ 180 181 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \ 182 DEFINE_PER_CPU(_type, _name) = _initvalue; \ 183 __typeof__(_type) _name##_early_map[NR_CPUS] __initdata = \ 184 { [0 ... NR_CPUS-1] = _initvalue }; \ 185 __typeof__(_type) *_name##_early_ptr __refdata = _name##_early_map 186 187 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \ 188 EXPORT_PER_CPU_SYMBOL(_name) 189 190 #define DECLARE_EARLY_PER_CPU(_type, _name) \ 191 DECLARE_PER_CPU(_type, _name); \ 192 extern __typeof__(_type) *_name##_early_ptr; \ 193 extern __typeof__(_type) _name##_early_map[] 194 195 #define early_per_cpu_ptr(_name) (_name##_early_ptr) 196 #define early_per_cpu_map(_name, _idx) (_name##_early_map[_idx]) 197 #define early_per_cpu(_name, _cpu) \ 198 *(early_per_cpu_ptr(_name) ? \ 199 &early_per_cpu_ptr(_name)[_cpu] : \ 200 &per_cpu(_name, _cpu)) 201 202 #else /* !CONFIG_SMP */ 203 #define DEFINE_EARLY_PER_CPU(_type, _name, _initvalue) \ 204 DEFINE_PER_CPU(_type, _name) = _initvalue 205 206 #define EXPORT_EARLY_PER_CPU_SYMBOL(_name) \ 207 EXPORT_PER_CPU_SYMBOL(_name) 208 209 #define DECLARE_EARLY_PER_CPU(_type, _name) \ 210 DECLARE_PER_CPU(_type, _name) 211 212 #define early_per_cpu(_name, _cpu) per_cpu(_name, _cpu) 213 #define early_per_cpu_ptr(_name) NULL 214 /* no early_per_cpu_map() */ 215 216 #endif /* !CONFIG_SMP */ 217 218 #endif /* _ASM_X86_PERCPU_H */ 219